cmake: set feature PSL if present

... make test 1014 pass when libpsl is used.

Closes curl#9391

CMakeLists.txt

@@ -1434,6 +1434,7 @@ _add_if("HTTPS-proxy"   SSL_ENABLED AND (USE_OPENSSL OR USE_GNUTLS OR USE_NSS))
 _add_if("unicode"       ENABLE_UNICODE)
 _add_if("threadsafe"    HAVE_ATOMIC OR (WIN32 AND
                         HAVE_WIN32_WINNT GREATER_EQUAL 0x600))
+_add_if("PSL"           USE_LIBPSL)
 string(REPLACE ";" " " SUPPORT_FEATURES "${_items}")
 message(STATUS "Enabled features: ${SUPPORT_FEATURES}")